This invention relates in general to rail vehicles and, in particular, to a new and useful subway vehicle for service in a tunnel or tunnel tube, having a circular or rounded cross-section, with the car body of the vehicle having an unsymmetrical cross-section and one of its longitudinal sides formed by a vertical side wall which is provided with the necessary windows and doors, while the roof and the other longitudinal side of the vehicle are substantially conformed to the cross-section of the tunnel or tunnel tube.